Did you go into "My Computer" and click on the 3 1/2 drive? Anyhow, do that again and hit "Properties" and see what the file size is, try to click on the disk and see if a window pops up with a file or files, try clicking on "Explore" and see what comes up, so on and so on.
I bet you have jpeg pics on the disk like you said, BUT you or someone could have used a zip program of sorts as well (is there a password on the disk?).
IF you can see the files, copy and past them ALL in a new folder, after that see if you can read them then. By the way, for a fail safe program to read them make sure you are opening them up in "Windows Picture and Fax Viewer", then if windows can't open them, it will tell you what program to use or if something is wrong with the file.
The tab lock is only for writing to the disk, it has nothing to do with reading the disk.
Don't get rid of that disk until we look into it more and you give more info.